In the cases of femur fractures, often it is resorted to the use of pertrochanteric nails for the treatment of the fracture. In several years a great variety of nails with even minimal differences between them have been realized, which able to put the surgeon in the conditions of treating the fracture. Each nail is normally coupled to one dedicated instruments.
In most cases, the installation provides for access from the proximal part of the femur for its insertion in the medullary canal. One or two locking devices are normally present in the proximal part of the nail while other locking devices are also present in the distal part.
The locking devices in the proximal area are normally one or two cephalic screws, with a thread suitable to grip in the cancellous bone present within the humeral head. Said screws are frequently blocked with appropriate systems placed by the nail head. This block positively prevents the screw from rotating and then modifying the mounting performed by the surgeon.
In case of using a single cephalic screw, even if blocked as said before, a great stability of the fragment of the femoral head is not obtained, as it is subject to rotational forces which are not counteracted by the screw itself.
Obviously, the situation improves in the case of use of two screws, or analogous systems, since the two devices normally act on two different, coplanar or non-coplanar, axes. In these conditions, the devices themselves will oppose to the force of rotation to which the head of the femur is subjected.
In any case, the grip in the cancellous bone of the femoral head is entrusted to the thread of said systems.
The invention of the present application refers to a pertrochanteric nail wherein there two fixing elements are provided, in the proximal part of the nail, inserted in the cancellous bone of the femoral head.
A similar nail is described for the proximal humerus in European patent EP 2258290 B1. In the Spanish patent ES 8 225 188 an application wherein two elements of proximal locking are provided is described, which are inclined so as to form with the nail axis a triangle, similarly to the present invention, but with the elements overlapping each other.
In European patent EP 2258290 B1 for humeral nail there is a similar arrangement with the fastening elements consisting of several screws for the grip in the bone and a stabilization screw of the blade-shaped element.
Said stabilization screw intersects the blade-shaped element and is inserted in a suitable hole, and then stabilizes the blade-shaped element, remaining free to move in any case on its own axis.
In such prior art devices, once implanted, it is barely possible to adjust the grip on the fracture, in order to adjust the correct insertion of the nail.